title: Blaschko lines and other patterns of cutaneous mosaicism.
abstract: The lines of Blaschko represent a classic pattern of cutaneous mosaicism that can be observed in a wide variety of congenital and acquired skin disorders. This contribution reviews the clinicopathologic spectrum of skin lesions that follow Blaschko lines. Four other patterns of mosaicism are also discussed: blocklike, phylloid, large patches without midline separation, and lateralization. We emphasize the differential diagnoses, clues to correct categorization, and associated findings of inflammatory, hypopigmented, and hyperpigmented lesions with a mosaic distribution. Clinical examples are used to illustrate genetic concepts such as functional X-chromosome mosaicism, type 1 and 2 segmental manifestations of autosomal dominant skin diseases, paradominant inheritance, and twin spotting.
authors.affiliation: The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, 530 First Avenue, Dermatology H-100, New York, NY 10016, USA.
authors.forename: Vered
authors.initials: V
authors.lastname: Molho-Pessach
authors.forename: Julie V
authors.initials: JV
authors.lastname: Schaffer
mesh_terms: D025063:Chromosome Disorders; D003937:Diagnosis, Differential; D006801:Humans; D009030:Mosaicism; D012871:Skin Diseases / Q000175:diagnosis* / Q000235:genetics*